JP7230185B2 - rotor and permanent magnet motor - Google Patents

Description

This application claims priority to a Chinese patent application entitled "Rotor and Permanent Magnet Motor" with application number 201811295293.5 filed on November 1, 2018, and hereby Incorporated by reference.

The present application relates to the technical field of drives, and more particularly to rotors and permanent magnet motors.

A permanent magnet motor mainly includes a stator and a rotor, the rotor includes a rotor core and permanent magnets, and the permanent magnets are mounted in permanent magnet grooves of the rotor core. When a symmetrical three-phase current flows on the stator side, since the three-phase stator is shifted by 120° in space, the current of the three-phase stator generates a rotating magnetic field in space, and the rotor moves due to the electromagnetic force in the rotating magnetic field. At this time, electrical energy is converted into kinetic energy. In addition, when the permanent magnet produces a rotating magnetic field, the windings of the three-phase stator are under the action of the rotating magnetic field, and the armature reaction induces a three-phase symmetrical current, at which time the kinetic energy of the rotor is converted into electrical energy. be done.

In the conventional permanent magnet motor, the magnetic field generated by the permanent magnet is fixed, so it is difficult to adjust the magnetic field inside the permanent magnet motor. If the power supply voltage is fixed, the maximum operating frequency of the permanent magnet motor is limited.

In view of this, in order to solve the problem of achieving both high-frequency and low-frequency efficiencies in conventional permanent magnet motors, a rotor and permanent magnet motor capable of achieving both high-frequency and low-frequency efficiencies are provided. is required.

A rotor comprising a rotor core, at least two first permanent magnets and at least two second permanent magnets, wherein permanent magnet grooves are formed in axial end faces of the rotor core, and the permanent magnet grooves are formed in the rotor core. Circumferentially spaced apart from each other in the axial end face of the rotor core. Two permanent magnets are installed in the permanent magnet groove of the rotor core along the axial direction, and one permanent magnet is connected in series with one of the second permanent magnets in the radial direction of the rotor core. disposed in the permanent magnet groove to form a permanent magnet pole;
The portions of the rotor core respectively located between two circumferentially adjacent permanent magnet poles form alternating magnetic poles, and the permanent magnet poles form magnetic paths passing through the alternating magnetic poles.

In one embodiment, the coercive force of the first permanent magnet is smaller than the coercive force of the second permanent magnet, and in each permanent magnet groove , in the radial direction of the rotor core, the first permanent magnet 2 located on one side farther from the center of the rotor core than the permanent magnets.
In one embodiment, the permanent magnet grooves are evenly spaced in the circumferential direction of the rotor core and are arranged on the axial end face of the rotor core.
In one embodiment, the permanent magnet poles are arranged with the direction of the magnetic poles in the radial direction of the rotor core.
In one embodiment, in each permanent magnet groove , the first permanent magnets are installed to overlap the second permanent magnets in the radial direction of the rotor core.
In one embodiment, in each permanent magnet groove , the first permanent magnet is flush with both ends of the second permanent magnet in the circumferential direction of the rotor core.
In one embodiment, the cross-sectional shape of the permanent magnet poles is rectangular or V-shaped with an opening away from the center of the rotor core.
In one embodiment, a line connecting both ends of each permanent magnet pole in the circumferential direction of the rotor core and the center of the rotor core forms a first central angle, and the first central angle is π/p and less than 1.5π/p, where p is half the sum of the number of said permanent magnet poles and said alternating magnetic poles.
In one embodiment, the rotor core is formed with magnetic shield grooves in axial end faces, and the magnetic shield grooves extend to both ends of the permanent magnet poles in the circumferential direction of the rotor core.

A permanent magnet motor includes a stator and a rotor as described above, the rotor being rotatably mounted within the stator.

In the rotor and the permanent magnet motor according to the present application, the permanent magnet poles are connected in series with each other in the radial direction of the rotor core and are formed by the first permanent magnet and the second permanent magnet having different coercive forces. It is possible to adjust the magnetic field of the permanent magnet motor by changing the magnetic field strength of the permanent magnet having In addition, when alternating magnetic poles are combined with permanent magnetic poles and a permanent magnet motor is magnetically adjusted by a magnetizing current, the formed circuit passes through the permanent magnetic poles and the alternating magnetic poles, and there is no permanent magnet in the alternating magnetic poles. The interference with the magnet is reduced, reducing the difficulty of magnetizing permanent magnets with low coercive force, and the presence of alternating magnetic poles makes the permanent magnet poles alternate, so the amount of permanent magnets used is greatly reduced. .

In order to more clearly describe the technical means in the embodiments or the prior art of the present application, the drawings necessary for describing the embodiments or the prior art will be briefly described below. The drawings described are only examples of the present application, and those skilled in the art can obtain other drawings from the disclosed drawings without creative efforts.

It is a structural diagram of a rotor in the embodiment of the present application. 2 is a distribution diagram of the magnetic field of the rotor shown in FIG. 1; FIG. FIG. 4 is a structural diagram of a rotor in another embodiment of the present application;

In order to facilitate the understanding of the invention, the invention will now be fully described with reference to the associated drawings. The drawings show preferred embodiments of the invention. This invention may, however, be embodied in many forms and is not limited to the embodiments set forth herein. Rather, these examples are provided for the purpose of providing a clearer and more complete understanding of the present disclosure.

It should be noted that when a means is described as being "fixed to" another means, it may be located directly on the other means, or there may be another means in between. When a means is identified as being "connected to" another means, it may be directly connected to the other means, or there may be another means in between at the same time. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for descriptive purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. As used herein, the terminology used in the description of the invention is for describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of any one or more of the associated listed items.

1 and 2, a permanent magnet motor according to one embodiment of the present application includes a stator and a rotor 100. The rotor 100 is coaxially mounted within the stator, and the rotor 100 and the stator are disposed between the rotor 100 and the stator. has an air gap so that the rotor 100 rotates with respect to the stator.

In one embodiment, the stator includes a stator core and an armature winding, the stator core being press-formed from a soft magnetic silicon steel plate, and a plurality of circumferentially-spaced magnets within the stator core. Teeth are installed and armature windings are wound on each tooth, and the windings of the armature, when energized, produce a rotating magnetic field and act to promote the rotation of the rotor 100 .

In one embodiment, the rotor 100 includes a rotor core 10 and permanent magnets. The rotor core 10 is formed by pressing a soft magnetic silicon steel plate. Installed on the end face in the axial direction. Specifically, a permanent magnet groove 11 is formed in the axial end face of the rotor core 10 , and the permanent magnet is installed in the permanent magnet groove 11 of the rotor core 10 along the axial direction.

In one embodiment, the permanent magnet grooves 11 are opened in the axial end face of the rotor core 10 at intervals in the circumferential direction of the rotor core 10 .

In one embodiment, the permanent magnets include a first permanent magnet 20 and a second permanent magnet 30, the first permanent magnet 20 being different in coercive force than the second permanent magnet 30, and the first permanent magnet 20 and the second permanent magnet 30 being separated from each other. magnet 30
, the number of which is the same and is at least two, one first permanent magnet 20 and one second permanent magnet 30 are mounted together in one permanent magnet groove 11, and are arranged radially of the rotor core 10. , the first permanent magnet 20 and the second permanent magnet located in the same permanent magnet groove 11 are connected in series to form one permanent magnet pole 40 together.

In one embodiment, the portion of the rotor core 10 located between two permanent magnet poles 40 adjacent in the circumferential direction is one alternating magnetic pole 50 (the alternating magnetic pole 50 is formed in a portion of the rotor core 10 where no permanent magnet is installed). ) are formed, and the permanent magnet poles 40 form a magnetic path passing through the stator and the alternating magnetic poles 50 .

In the permanent magnet motor according to this embodiment, the permanent magnet poles 40 are formed by the first permanent magnet 20 and the second permanent magnet 30 connected in series in the radial direction of the rotor core 10, and the first permanent magnet 20 and the second permanent magnet 30 are connected in series. Due to the different coercive force with the permanent magnet 30, the permanent magnet motor can magnetize and saturate the permanent magnet with low coercive force under the condition of low speed and large torque by magnetizing current, so as to meet the needs. Increase the magnetic field strength inside the permanent magnet motor, when the permanent magnet motor operates at high speed and small torque, the magnetization current will reduce the degree of magnetization of the permanent magnet with low coercive force, so that the permanent magnet motor The magnetic field strength of the permanent magnet motor can be adjusted by reducing the magnetic field strength inside the . As a result, the permanent magnet motor can achieve both high-frequency efficiency and low-frequency efficiency. , the demagnetization resistance ability of the permanent magnet with low coercive force is improved, and the permanent magnet pole 40 is combined with the alternating magnetic pole 50, and the magnetizing current is used to magnetically adjust the permanent magnet motor. and the alternating magnetic poles 50, and the absence of permanent magnets in the alternating magnetic poles 50 reduces interference with the circuit, thus reducing the difficulty of magnetizing permanent magnets with low coercivity. In addition, since the alternating magnetic poles 50 are present, the permanent magnet poles 40 are alternately present, so that the amount of permanent magnets used is greatly reduced.

Furthermore, in one embodiment, the permanent magnet grooves 11 are evenly spaced in the circumferential direction of the rotor core 10 and correspondingly the at least two first permanent magnets 20 are evenly spaced in the circumferential direction of the rotor core 10 . , and at least two second permanent magnets 30 are also spaced uniformly.

Specifically, in one embodiment, the number of permanent magnet grooves 11 is at least three, and correspondingly, the number of first permanent magnets 20 and second permanent magnets 30 is also at least three.

In one embodiment, the center of the figure formed by straight lines connecting the centers of at least three permanent magnet grooves 11 in turn overlaps the center of the rotor core 10 . In this case, the center of the figure formed by straight lines connecting in order the centers of the first permanent magnets 20 mounted in the at least three permanent magnet grooves 11 overlaps the center of the rotor core 10, and the at least three permanent magnet grooves 11 are aligned. The center of the figure formed by straight lines connecting the centers of the second permanent magnets 30 mounted therein also coincides with the center of the rotor core 10 .

Specifically, in one embodiment, the first permanent magnets 20 and the second permanent magnets 30 installed in the respective permanent magnet grooves 11 in the radial direction of the rotor core 10 are overlapped to form the first permanent magnets 20 and 30 . The effect of series connection of the permanent magnet 20 and the second permanent magnet 30 is ensured.

Furthermore, in one embodiment, both ends of the first permanent magnet 20 and the second permanent magnet 30 installed in each permanent magnet groove 11 in the circumferential direction of the rotor core 10 are flush with each other. The first permanent magnet 20 and the second permanent magnet 30 have the same size in the circumferential direction.

In one embodiment, each of the first permanent magnets 20 and each of the second permanent magnets 30 installed in the circumferential direction of the rotor core 10 has a rectangular cross section. The permanent magnet poles 40 formed by connecting the magnets 30 in series are rectangular. At this time, the linear figure connecting the centers of at least three permanent magnet poles 40 in turn becomes a regular polygon, and the magnetic pole direction of each permanent magnet pole 40 is along the radial direction of the rotor core 10.

Specifically, in one embodiment, a straight line connecting both ends of each permanent magnet pole 40 in the circumferential direction of the rotor core 10 and the center of the rotor core 10 forms a first central angle θ1. Angle θ 1 is greater than π/p and less than 1.5π/p , where p is 1/2 the sum of permanent magnet pole 40 and alternating magnetic pole 50 . The magnetic field of the alternating magnetic poles 50 is provided by the magnetic field of the permanent magnet poles 40, and when so installed, the first central angle θ1 of the permanent magnetic poles 40 becomes the second central angle θ2 of the alternating magnetic poles 50 ( It can be ensured that both ends of each alternating magnetic pole 50 are larger than the central angle formed by the straight line connecting to the center of the rotor core 10, so that the magnetic flux density inside the permanent magnet motor can be guaranteed, It can be ensured that the second central angle θ2 of the alternating magnetic poles 50 is not too small.

In one embodiment, the coercive force of the first permanent magnets 20 is smaller than the coercive force of the second permanent magnets 30 , and the first permanent magnets 20 are closer to the center of the rotor core 10 than the second permanent magnets 30 in the radial direction of the rotor core 10 . The first permanent magnet 20 located on the one side away from, ie, having a relatively small coercive force, is located outside (one side closer to the stator) of the second permanent magnet 30 having a relatively large coercive force. Since the magnetic adjustment magnetic field is generated by the stator, if the first permanent magnet 20 is placed outside the second permanent magnet 30, the magnetic adjustment magnetic field will directly act on the first permanent magnet 20, resulting in a relatively large coercive force. When the second permanent magnet 30 having a relatively small coercive force is placed outside the first permanent magnet 20 having a relatively small coercive force (at this time, the magnetic adjustment magnetic field first acts on the second permanent magnet 30, and then the first permanent magnet 20 and a loss occurs when the magnetic field acts on the second permanent magnet 30), the magnetic adjustment becomes easier.

In addition, the magnetization current of the first permanent magnet 20 with low coercive force is relatively small, and the width of the first permanent magnet 20 is set to a second width so as to ensure that demagnetization does not occur when the permanent magnet motor operates normally. The width of the permanent magnet 30 is larger than that of the permanent magnet 30, and the sizes of the first permanent magnet 20 and the second permanent magnet 30 are selected so as to satisfy the following relationship.
50A/m<(Hl×dl+H2×d2)/(dl+d2)<400A/m
where dl is the width of the second permanent magnet 30 with high coercive force, d2 is the width of the first permanent magnet 20 with low coercive force, and H1 is the width of the second permanent magnet 30 with high coercive force. coercive force, and H2 is the coercive force of the first permanent magnet 20 having a low coercive force.

Referring to FIG. 3, in another embodiment, the cross-sectional shape of each first permanent magnet 20 and each second permanent magnet 30 in the circumferential direction of the rotor core 10 may not be rectangular. The cross-sectional shapes of the magnet 20 and each of the second permanent magnets 30 may both be V-shaped with openings away from the center of the rotor core 10 . That is, each first permanent magnet 20 includes two portions arranged to form an angle, each second permanent magnet 30 includes two portions arranged to form an angle, and the first permanent magnet 20 includes two portions arranged to form an angle. A permanent magnet pole 40 formed by the magnet 20 and the second permanent magnet 30 is V-shaped. In this manner, the magnetic flux density of the permanent magnet motor is improved and the torque density of the permanent magnet motor is improved without changing the first center angle θ1 of the permanent magnet pole 40 as compared with the above embodiment.

In one embodiment, magnetic shield grooves 12 are formed in axial end faces of rotor core 10 , and magnetic shield grooves 12 extend to both ends of permanent magnet poles 40 in the circumferential direction of rotor core 10 . By providing the magnetic shield groove 12, the magnetic flux of the permanent magnet pole 40 can be prevented from being confined to its own end, and the magnetic leakage of the permanent magnet motor can be reduced.

Embodiments of the present application further provide a rotor 100 included in the permanent magnet motor described above.

The rotor 100 and permanent magnet motor according to embodiments of the present application have the following beneficial effects.
1. The permanent magnet poles 40 are connected in series with each other in the radial direction of the rotor core 10, and are formed by the first permanent magnet 20 and the second permanent magnet 30 with different coercive forces, so that the permanent magnet motor has a speed of In the low and high torque state, the magnetizing current magnetizes and saturates the permanent magnet with low coercive force, so that the magnetic field strength inside the permanent magnet motor is increased to meet the needs, so that the permanent magnet motor can achieve high speed and low torque. When the magnetization current is activated, the degree of magnetization of the permanent magnet with low coercive force is reduced, and the magnetic field inside the permanent magnet motor is reduced to meet the needs, thus adjusting the magnetic field strength of the permanent magnet motor. This allows the permanent magnet motor to achieve both efficiency at high and low frequencies.
2. The permanent magnet poles 40 and the alternating magnetic poles 50 are alternately arranged in the circumferential direction of the rotor core 10, and the permanent magnets do not exist in the alternating magnetic poles 50. Therefore, it is difficult to magnetize permanent magnets with low coercive force. and the presence of alternating magnetic poles 50 reduces the amount of permanent magnets used.
3. In the radial direction of the rotor core 10, the first permanent magnet 20 with coercive force is located outside the second permanent magnet 30 with high coercive force, and when magnetic adjustment is required, the magnetic adjustment magnetic field by the stator is Acting directly on the first permanent magnet 20 facilitates magnetic adjustment.

Various technical features according to the above-described embodiments may be combined arbitrarily, but for the sake of brevity, descriptions of all combinations of technical features according to the above-described embodiments are omitted. However, as long as there is no contradiction in the combination of these technical features, all are included in the scope described in this specification.

The above examples are merely embodiments in the present application, the description of which is more specific and detailed, but should not be understood as limiting the scope of the claims of the application. For those skilled in the art, various modifications and improvements are possible without departing from the spirit of the present application, which fall within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application is based on the attached claims.

Claims (9)

a rotor core (10);
at least two first permanent magnets (20) and at least two second permanent magnets (30);
including
Permanent magnet grooves (11) are formed in the axial end face of the rotor core (10), and the permanent magnet grooves (11) are spaced apart in the circumferential direction of the rotor core (10). is opened in the axial end face of
The first permanent magnets (20) differ from the second permanent magnets (30) in coercivity, and the at least two first permanent magnets (20) and the at least two second permanent magnets (30) are axially installed in the permanent magnet groove (11) of the rotor core (10) along the direction, and one of the first permanent magnets (20) is installed in the radial direction of the rotor core (10) to one of the second permanent magnets ( 30) are arranged in one permanent magnet groove (11) to form a permanent magnet pole (40), and
The portions of the rotor core (10) respectively located between two circumferentially adjacent permanent magnet poles (40) form alternating magnetic poles (50) in which the permanent magnets are not installed , and the permanent magnet poles ( 40) forms a magnetic path passing through the alternating magnetic poles (50),
A straight line connecting both ends of each permanent magnet pole (40) in the circumferential direction of the rotor core (10) and the center of the rotor core (10) forms a first central angle (θ1). 1 central angle (θ1) is larger than π/p and smaller than 1.5π/p, where p is the sum of the numbers of the permanent magnet poles (40) and the alternating magnetic poles (50) 1/2. The coercive force of the first permanent magnet (20) is smaller than the coercive force of the second permanent magnet (30), and each permanent magnet groove (11) has a radial direction of the rotor core (10). A rotor (100) according to claim 1, characterized in that one permanent magnet (20) is located on one side further away from the center of said rotor core (10) than said second permanent magnet (30). 2. The permanent magnet grooves (11) according to claim 1, characterized in that the permanent magnet grooves (11) are evenly spaced in the circumferential direction of the rotor core (10) and are installed on the axial end face of the rotor core (10). rotor (100). The rotor (100) according to claim 3, characterized in that the permanent magnet poles (40) are arranged with a magnetic pole direction in a radial direction of the rotor core (10). The first permanent magnet (20) and the second permanent magnet (30) are installed in each permanent magnet groove (11) so as to overlap with each other in the radial direction of the rotor core (10). 4. A rotor (100) according to clause 3. In each permanent magnet groove (11), the first permanent magnet (20) is flush with both ends of the second permanent magnet (30) in the circumferential direction of the rotor core (10). A rotor (100) according to claim 3. The rotor (100) of claim 1, wherein the cross-sectional shape of the permanent magnet poles (40) is rectangular or V-shaped with an opening away from the center of the rotor core (10). The rotor core (10) has a magnetic shield groove formed in an end face in the axial direction, and the magnetic shield groove extends to both ends of the permanent magnet pole (40) in the circumferential direction of the rotor core (10). A rotor (100) according to claim 1, characterized in that: A permanent magnet comprising a stator and a rotor (100) according to any one of claims 1 to 8, wherein the rotor (100) is rotatably mounted in the stator motor.

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